From 4910cfd150342ec7b038892262923c725a9c4001 Mon Sep 17 00:00:00 2001
From: Sham Muthayyan <smuthayy@codeaurora.org>
Date: Wed, 7 Sep 2016 16:44:28 +0530
Subject: PCI: qcom: Force GEN1 support

Change-Id: Ica54ddb737d7b851469deab1745f54bf431bd3f0
Signed-off-by: Sham Muthayyan <smuthayy@codeaurora.org>
---
 drivers/pci/host/pcie-qcom.c | 13 +++++++++++++
 1 file changed, 13 insertions(+)

--- a/drivers/pci/dwc/pcie-qcom.c
+++ b/drivers/pci/dwc/pcie-qcom.c
@@ -129,6 +129,8 @@
 #define PCIE20_v3_PARF_SLV_ADDR_SPACE_SIZE	0x358
 #define SLV_ADDR_SPACE_SZ			0x10000000
 
+#define PCIE20_LNK_CONTROL2_LINK_STATUS2        0xA0
+
 struct qcom_pcie_resources_2_1_0 {
 	struct clk *iface_clk;
 	struct clk *core_clk;
@@ -218,6 +220,7 @@ struct qcom_pcie {
 	struct phy *phy;
 	struct gpio_desc *reset;
 	struct qcom_pcie_ops *ops;
+	uint32_t force_gen1;
 };
 
 #define to_qcom_pcie(x)		dev_get_drvdata((x)->dev)
@@ -532,6 +535,11 @@ static int qcom_pcie_init_2_1_0(struct q
 
 	/* wait for clock acquisition */
 	usleep_range(1000, 1500);
+	if (pcie->force_gen1) {
+		writel_relaxed((readl_relaxed(
+			pcie->pci->dbi_base + PCIE20_LNK_CONTROL2_LINK_STATUS2) | 1),
+			pcie->pci->dbi_base + PCIE20_LNK_CONTROL2_LINK_STATUS2);
+	}
 
 
 	/* Set the Max TLP size to 2K, instead of using default of 4K */
@@ -1382,6 +1390,8 @@ static int qcom_pcie_probe(struct platfo
 	struct dw_pcie *pci;
 	struct qcom_pcie *pcie;
 	int ret;
+	uint32_t force_gen1 = 0;
+	struct device_node *np = pdev->dev.of_node;
 
 	pcie = devm_kzalloc(dev, sizeof(*pcie), GFP_KERNEL);
 	if (!pcie)
@@ -1403,6 +1413,9 @@ static int qcom_pcie_probe(struct platfo
 	if (IS_ERR(pcie->reset))
 		return PTR_ERR(pcie->reset);
 
+	of_property_read_u32(np, "force_gen1", &force_gen1);
+	pcie->force_gen1 = force_gen1;
+
 	res = platform_get_resource_byname(pdev, IORESOURCE_MEM, "parf");
 	pcie->parf = devm_ioremap_resource(dev, res);
 	if (IS_ERR(pcie->parf))
